HER2 Control Cell Lines Why do we use control cell lines? Oracle HER2 control cell lines are designed as assay quality controls. They ensure procedural accuracy of the Leica BOND Oracle TM HER2 IHC System. The Oracle HER2 control cell lines validate: • reagent optimization and performance • correct protocol implementation • instrumentation performance The Oracle 2+ cell line affords superior assay validation by representing the borderline 2+ expression level, the expression level most likely to be affected by any variation in an assay. Cell lines do NOT validate laboratory specimen preparation procedures or replace the requirement for appropriately fixed and processed in-house tissue controls. Important notes for evaluating the HER2 control cell lines A feature of the MDA-MB-175 1+ control cell line is a distinct growth pattern in which the cells form clusters. These clusters give rise to a continuous luminal brush border region across the cell cluster. This brush border staining will be stronger than that of the cell membrane and should not be included in the HER2 staining evaluation. It is the faint/barely perceptible incomplete cell membrane staining that is the correct HER2 oncoprotein 1+ staining pattern. Dot-like immunostaining of the Golgi region in the cytoplasm may also be observed in this cell line and should not be included in the HER2 staining evaluation. (For more information see Bond Oracle HER2 IHC System Interpretation Guide). Minimal natural variation of immunohistochemical profile will be seen between growth batches of cell lines utilized within the Leica Bond Oracle HER2 IHC System. This natural variation is well within acceptable tolerance levels of a biological entity and does not affect the evaluation or performance of the system. The Oracle HER2 control cell lines display consistent homogeneous staining as they are manufactured from a clonal population whose cells have a consistent gene/protein expression profile. When evaluating the HER2 control cell lines, the observer must be aware that the percentage rules applying to tissue (over the page) do not apply to cell lines. A valid assay with the Oracle HER2 Control Slide shows the following: 3+ 2+ 1+ 0 Presence of strong brown, complete cell membrane staining in the 3+ control cell line, SK-BR-3 No staining in the 0 control cell line, MDA-MB-231 Presence of faint/barely perceptible brown, incomplete cell membrane staining in the 1+ control cell line, MDA-MB-175 Presence of weak to moderate brown, complete cell membrane staining in the 2+ control cell line, MDA-MB-453 95.10603 Rev C 02/2014 Copyright © by Leica Biosystems Newcastle Ltd, Newcastle, UK, 2012 LEICA and the Leica Logo are registered trademarks of Leica Microsystems IR GmbH.